This invention relates to a remote television control, and more particularly, to a channel-changing control which responds to acoustical signals emitted from a remote location.
Conventional remote control systems for television sets are normally wired into the sets. Usually, it is not feasible to retrofit existing television sets not having a remote control capability with conventional remote control systems.
We are aware of one new type of acoustical control system which can be affixed to a standard television set so that the set can be controlled from a remote location. That system is disclosed in applicant's application Ser. No. 341,935, filed Mar. 16, 1973, entitled REMOTE TELEVISION CONTROL UNIT, now abandoned. That arrangement works quite satisfactorily. However, for practical reasons, it is desirable to provide a tuner shaft actuator remote from the tuner shaft and mechanically coupled thereto by a simple force transmitter requiring minimal connections to the shaft.
None of the prior television channel changing systems of which we are aware are adapted for retrofitting on almost any standard television receiver. The elaborate type of systems exemplified in U.S. Pat. Nos. 3,757,303 and 3,854,123 are wired right into the chassis of the television set. Those systems are specially designed for the particular sets in which they operate and the systems cannot be incorporated into other different television sets.
Other control mechanisms such as the one disclosed in U.S. Pat. No. 2,769,344 require the viewer to yank on a rip cord each time he wishes to change channels. In that type of system, the knob has to be screwed to the front of the television set housing. This not only makes it difficult to switch the control mechanism from set to set, it also disfigures the television set. An even worse disadvantage of that type of prior system stems from the fact that some means must be provided to anchor the television set to its supporting surface so that it will not be pulled over as the viewer changes channels. Such instability was not so much a problem in the early days of television when the TV receivers were very large and heavy floor models. However, that mechanism would be completely unsatisfactory for use on the small, lightweight, table model TV sets that are prevalent today. Unless the set was anchored, the viewer would pull it off the table everytime he tried to change channels. Furthermore, that prior control mechanism was simply a channel changer; the viewer still had to turn the set on and off manually.
Other prior remote television control systems have other disadvantages which militate against their wider use and acceptance. Some require bulky actuators connected to the tuner shaft. If there are any other television controls such as fine tuning, power or volume controls, in the vicinity of the tuner shaft as there invariably are, the actuator cannot be installed on that set. Still other prior TV remote control mechanisms require cable connections between the television set and the viewer's position. U.S. Pat. No. 2,907,217 shows an arrangement having both of the aforesaid drawbacks.
Another major difficulty encountered when trying to design a universal television remote control system which can be accommodated to most existing television sets stems from the fact that not only are the tuner detent characteristics different from set to set, but they also vary from channel to channel within the same tuner due to aging, wear, etc. In other words, as a given tuner is indexed from channel to channel, different applied forces may be required to change between channels. The detent or spring affecting tuner travel between adjacent heavily used channels might be relatively worn or weak so that relatively little force is required to switch between those channels. On the other hand, the corresponding elements associated with relatively little-used channels may retain their original conditions so that more force is required to index through those channels. Any practical channel changer must be able to cope with these different torque requirements. And since there is no pattern to these requirements, a simple manual adjustment will not overcome that problem.